Boris Johnson wants a Canada Plus-type free trade deal with the EU.  The latter is willing to negotiate one – but for Great Britain only.

The Prime Minister’s new Brexit negotiating proposal is an attempt to square this circle.  It can be viewed in one of three ways.

The first is that the plan paves the way for exactly such a deal, by taking the whole of the UK out of the Customs Union (in effect) and then, in time, allowing Northern Ireland to decide for itself to come out of the Single Market.

The second is that is essentially the old EU free-trade-deal-for-Great-Britain-only plan dressed up in new clothes.  This is because Northern Ireland will remain in the Single Market – to cut a long story short – until 2025 with no guarantee of leaving it afterwards.

The third is that it is ambiguously poised between those first two outcomes, with all ultimately depending on what Northern Ireland’s institutions – assuming that they are up and running again – eventually decide to do.  Either way, the Johnson plan appears to presume the continutation of the remaining contents of the Withdrawal Agreement.

So what will Parliament and the EU make of the plan – which undoubtedly proposes the scrapping of the Agreement’s UK-wide backstop architecture, which would effectively keep the whole country in the Customs Union?  (Under its terms, Great Britain would be in the Customs Union.  Northern Ireland in a Customs Union.  Theresa May insisted on this version precisely because she was unwilling to sign up to a Northern Ireland-only backstop.)

The former Prime Minister’s deal was brought down primarily because neither Labour, the DUP nor the “Spartans” would support it.  The early Parliamentary signs for Johnson’s proposal are good.  The DUP appears to have been squared by Downing Street.  The Spartans seem unwilling to be more royal than the king, and prepared to follow where the DUP leads.  There is also an English nationalist streak in some Conservative MPs, who are not unhappy about seeing Great Britain and Northern Ireland diverge, in the way that the plan allows for.

Meanwhile, the crucial Labour component are a band of MPs who are insistent that the referendum result be respected, most of whom represent strongly pro-Leave constituencies.  Seventeen of them have been identified as part of the all-party “MPs for a Deal” group.  Theresa May’s constant hope was that this band would enter the Government lobby to vote for the Withdrawal Agreement.  It never did: party loyalty trumped its political yearnings.  Early signs are that it may be different this time.

So Johnson appears potentially to be in a good position in Parliament as far as this proposal is concerned.  But there is a nasty fly in his ointment – namely, the Benn Act.  The EU side of the negotiating table knows that the Act stipulates as follows: if MPs haven’t approved leaving the EU without a deal by 19 October, the Prime Minister must seek an extension until the end of January next year.

The EU therefore has less incentive to negotiate on the basis of Johnson’s proposal that it would had the Benn Act not been passed – because on the face of it the Act removes the possibility of Brexit by October 31.  The EU believes that neither it nor the UK will therefore have to face a disruptive No Deal after that date.

So it can hang on, rebuff Johnson’s plan – and see what happens next.  True, that might be a general election which returns the Prime Minister with a big majority.  But it might also be that his government collapses and Parliament pushes for a second referendum, under either his premiership or someone else’s.

Which way will it jump?  It is very important to note that the EU has real problems of its own with the Johnson proposal.

After all, it offers Stormont a veto over the Single Market, and would take Northern Ireland out of the Customs Union. The Irish Government will loathe that second element and the market’s champions the first.

So the signs as we write are not good – although the EU will not want to be seen to collapse the negotiation, and that Parliament might pass the plan may give it pause for thought.

What is undoubtedly the case is that, had the Benn Act not been passed, a No Deal Brexit would loom on October 31. That would have concentrated minds wonderfully both in Parliament and in Brussels.  But there is such an Act and the pressure is off both.

MPs know that they could oppose any new deal without thus bringing about a No Deal Brexit (assuming the wording of the Act is legally watertight).  And the EU knows that it can refuse to agree one in the first place without a mutually damaging No Deal outcome on October 31.

So had Philip Hammond and the other 20 rebels not voted with Benn, his Bill would have fallen at Second Reading, it would not have become law, we would clearly be heading for Brexit at the end of this month – and Johnson’s negotiating position would be far stronger.  We like to steer clear here of emotionally-charged terms such as sabotage, but it is very hard not to deploy it.